sysdeps/powerpc/fpu/k_sinf.c

   1 /* k_sinf.c -- float version of k_sin.c
   2    Copyright (C) 2011-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If
  18    not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <float.h>
  21 #include <math.h>
  22 #include <fenv.h>
  23 #include <math_private.h>
  24
  25
  26 static const float twom27 =  7.4505806000e-09;
  27 static const float half   =  5.0000000000e-01;
  28 static const float S1     = -1.6666667163e-01;
  29 static const float S2     =  8.3333337680e-03;
  30 static const float S3     = -1.9841270114e-04;
  31 static const float S4     =  2.7557314297e-06;
  32 static const float S5     = -2.5050759689e-08;
  33 static const float S6     =  1.5896910177e-10;
  34
  35
  36 float
  37 __kernel_sinf (float x, float y, int iy)
  38 {
  39   float z, r, v;
  40   float ix;
  41   ix = __builtin_fabsf (x);
  42   if (ix < twom27)
  43     {                           /* |x| < 2**-27 */
  44       if (ix < FLT_MIN && ix != 0.0f)
  45         __feraiseexcept (FE_UNDERFLOW|FE_INEXACT);
  46       else
  47         __feraiseexcept (FE_INEXACT);
  48       return x;
  49     }
  50   z = x * x;
  51   v = z * x;
  52   r = S2 + z * (S3 + z * (S4 + z * (S5 + z * S6)));
  53   if (iy == 0)
  54     return x + v * (S1 + z * r);
  55   else
  56     return x - ((z * (half * y - v * r) - y) - v * S1);
  57 }